発芽の光感性

I. 種子の発芽の光週的傾向.

抄録

1. “Photoperiodicity” has been recognized in the germination behavior of “Light-favoured Seeds” and “Dark-favoured Seeds”.
2. Many of “Light-favoured Seeds” are “Short Day Seeds”. namely, seeds having in its germination behavior a tendency of “Short Day Plants”. Each species of them has a certain maximum photoperiod favorable for germination. Accordingly their germinattion percentage when exposed to continuous artificial light were lower than the percentage induced by their maximum photoperiod favorable for germination.
3. The favorable photoperiod for the germination of Epilobium covered a wide range of durations (100minutes to 21hours). The seeds of this plant was considered as “Short Day Seeds” in view of the fact that the better germination percentage was promoted by the interruption of the light period with dark intervals than continuous illuminating.
4. “Dark-favoured Seeds” are considered as one form of “Short Day Seeds”. 5. The author couldn't recognized a type which may be called “Long Day Seeds” which show the rate dropped by the interruption of the light period with dark intervals. However, spores of a fern (Athyrium niponicum) obviously presented a charactor of “Long Day Plant”. The writer wish to express my cordial thanks to Professor T. Miwa for his kind guidance during the course of this study and also to Professor S. Hattori and Mr. M. Hasegawa who gave me most valuable suggestions and directions regarding the present work. The writer also extend his thanks to Messrs. T. Oofusa, G. Shimogawara and Miss I. Shihira who rendered assistance througout the experiments, and to Mr. K. Hirano, M. Chihara and Members of local experimental stations of Japan Tobacco Monopoly Agency, and Mr. Goda (Daiichi Gardening Company at Shibuya) who collected and offered precious materials for this study.